Electrical transformer.



No. 857 062. a PATENTED JUNE 18 1962.

' J. D. HILLIARD.

ELECTRICAL TRANSFORMER.

APPLICATION FILED NOV.20,1906,

UNITED STA' I ES PATENT OFFICE;

JOHN D, HILLIARD, or ALBANY, NEW YORK.

ELECTRICAL TRANSFORMER.

Specification of Letters Patent.

Patented June 18, 1907.

Application filed November 20, 1906. Serial No. 344,208.

comp'anying drawing.

My invention relates to electrical transformers, and especially to those which are mounted in cases filled with oil. Heretoiore,

' such transformers have been built with taps connected to various points on the windings so that the ratio of transformation could be changed whendesired; but the taps have been so located that in orderto make the chan c, it has been necessary to unbolt the top 0 "the transformer and feel around in the oil to find the proper contacts, or to withdraw theoil from the case so as to expose the same. Such procedure makes the work of changing very slow, and it is the object of my invention to produce an arrangement whereby it will be unnecessary to open the casing or to withdraw the oi the cl'iange be ing made from the outside of the casing with speed and certainty. I

in order to attain my object, I mount a switch or switches directly within the trans former casing, and operate the same by means of a rod or rods projecting through the top. The contact points of the switches are connected to various taps on the transformer windings, and each set is arranged on the are I of a circle having the switch arm and its controlling rod pivoted at its center. Suitable operating handles'are provided, having indicating pointers and controlling fixed points on the top of the casing. The contact )ieces and insulators are preferably inclosmf in a case or compartment separate from that containing the transformer windings, so that any carbon which may be formed in the oil will be prevented from falling and being deposited upon the transformer windings.

With the arrangement thus outlined a change in ratio transformation can bcmade within one minute, whereas with the old method. approximately an hour is required to do the same work. The handles for operating my switches are preferably corrugated pieces of wood or other suitable material protected at their lower ends by procelain insulators. j i

In the accompanying drawings Figure 1 is a sectional view of an oil switch with my invention applied thereto. Fig. 2 is a top plan View with the top of the switch casing removed. Fig. 3 is a diagram of the connections of the primary and secondary windings, and of the switches. i

in the drawings I. have illustrated a typ ical form of transformerincluded in a metal casing C provided with a cover secured thereon by bolts or otherwise in any well known or suitable manner. The casing is filled with oil to a level considerably above the top of the transformer core. The leads for the windings pass through the top of the casing, being protected by insulating bushings i and i. From the windings taps 2, 3, i, 5, o, 7, 8, 9, are taken oil, and it is by varying the connections between and among these taps that I effect the desired changes in my ratios of transformation. For this purpose 1 provide the switch box constituting the characteristic feature of my invention, which is shown at B, with twoswitches, S, S, contained therein. The box itself is partlyor wholly incased in the oil within the main casing C, and the switches are adapted to be operated by insulated spindles or rods 1, 7* extending .up out of the box and through the top of the casing. Each of these rods or spindles is provided with a suitable grip, preferably corrugated, and with a porcelain or other insulater at the lower end. Danger in handling them is thus obviated. The box B is carried upon legs I), which also are in. the form of corrugated insulating bodies, these corrugations in each case acting of course to increase the surface of the insulation' Secured in the bottom of the box, but insulated therefrom by suitable bushings, are two series of contacts s, s, s", s, s, 5;, arranged on the arc of circles whose centers are in the axes of the operating rods 1-, r. Pivoted on each center, but insuiatcd from the rod. and the box, are switch blades .9, 8 which are adapted to be turned by the rods 1' or r to sweep over the contacts 8, s 8 s, Circuit connections to these blades may be completed in a variety of ways. I prefer to have the main taps 2 and 6 soldered into the lower end of the spindles of the switch blades, and with this arrangement it is of course desirable to either 0011 the wrre of the taps or to form a pig tail, so as to prevent any undesirable tor sional strain on the joint. of the switches is shown diagrammatically in Fig. 3, wherein w and w are the fixed or in- The connection 'vcricole portions oi -the secondary windings, from which the main tops 2 and 6 pass to t e switch blades 8 and 3 being secured thereto in the manner already described.

cictcd contacts, which are connected as follows: 8, 3 are connected together tln o gli the tops 3 and 7 s, s are connected to omen.

ent points on the windings of one side of the transformer by the tops 42 and 5, while if and. s are similarly connected to intermediate points on the other side of the winding by the tops 8 and 3. By the word side in this respect I mean right or left, in c mechan ical sense, not referring to the electrical relotion of the windings. The reason I crrongc my switches in this manner, providing two switches instead of one, is that I may preserve the synnnetry of the windings, and keep them balanced. lhe box B is provided with small openings which allow the oil to circulate through it, and the switches are thus covered in into, as regards their operating ports. At the some time it is entirely unnecessary torernove the of the casing in order to change the relation of the windinns. Each handle or operating rod is provi ed with. o pointer, set to coincide with the corresponding movable sii itch icrrn, end llround this pointer on the ore of a circle indicating points corresponding to the differ ent contacts. Suitable legends may be placed upon the switches, so that the blades may be set with exs ctnessl lt will be observed that many changes can be made in matters of-detsil without effecting my general design, and without deserting from the characteristic lectures 'o' the invention.

For the basic purpose ol'eilect ing changes in the arrangement and connection of the windings, the box B is of course not indispensable, as the switches S, S

could be niounted either directly on the top of the core, or upon a mounting plate, or upon brackets secured to the lid of the cesing, or in other ways. The manner l illustrate and describe, however, is preferable for several. reasons. It maintains a semicloscd chamber for the switches, which will receive and retain cny'carbon particles which may be formed, and prevent their falling on the windingsyit is easily applicable to several existing types of transformer and transformer casings and it requires no special fittings or attachments on the transformer or transfcrrner core.

Having thus described my invention, what I claim and desire to secure by Letters Pct-- entis: 6o.

a switch within sold casing, said switch hav These blcdes may be turned about over to oesooil to csufiicient depth to cover all of said contacts, and on operating bundle for the switch projecting out of the casing and crovidcd withjinflicati ng points con'espon ing in position with the contacts, substantially as described. P

2. All electrical transformer coinprisingc cesing containing oil, two compcrtinents in said casing, transformer windings immersed in the oil in one compartment and a regulcting switch also immersed in oil in the other compartment, said switch haying contact points on the transformer windings, and. en operziting handle projecting out of the casing, substantially as described.

3. All electriccl transformer comprising c casing containing oil, it transformer core and windings immersed in the oil, a regulating switch for changing the ratio of transformation, comprising contacts connected to r rious points on the transformer Wlm'llllgfl, it separate inclosure also containing all for said switch, insulating supports for l inclcscre adopted to rest upon the tram elmrmcrcorc, end an operating handle for the switch exlcndio. out of the casing, subsl cnticlly as described 4:. An electrical transformer comprising o main casing containing oil,j c core with pri mary and secondary windings immersed in the oil within the casing, 51 separate switch casing carried upon the transformer core and also immersed in the oil, a switch mounted in said separate casing and having cont-acts connected to taps from different points on one or both of the windings, and on operating handle for said switch extending out of the main casing through the top thereof, sub stantielly as described.

5. An electrical transformer comprising anicin casing containing oil, a core with primerry and secondary windings immersedin the oil within the casing, a separate-switch casing carried upon the transformer core and also immersed in the oil, a switch mounted in said separate casing and having (wont/cots connected to taps from diilere'nt points on one or both of the windings, and an operating handle for said switch extending outvol o the main casing through the top thereof, said handle being insulated from the operating ports of the switch lying ii/ithiuthc casing, s -ibstcntially as described. 1 i

In testimony whereof I aliix my signature in presence of two witnesses.

C. E. Pluisons, M. L. Srnrnc.

ill 

